also: ねつしせん
noun
gaze of keen interest; close attention
Used when someone is watching something with intense curiosity, fascination, or scrutiny. Often implies a focused, almost burning interest.
新製品に熱視線を送る。
They are watching the new product with keen interest.
彼の研究は学会から熱視線を浴びている。
His research is receiving close attention from the academic community.
注目 is a general term for attention or notice, while 熱視線 specifically conveys an intense, almost passionate gaze or scrutiny.
Compound of 熱 (netsu, 'heat') + 視線 (shisen, 'gaze'). The reading ねっしせん results from a common sound change (促音便) where つ becomes a small っ before certain consonants.